Microdosing devices for dispensing small and very small droplets are known from cosmetic or pharmaceutical medium dispensers, such as inhaler devices for liquid medical substances. These have a dosing chamber which can be filled from a medium reservoir with a quantity of liquid and which has at least one dispensing opening through which the liquid can escape after a flow resistance has been overcome. The flow resistance is determined in particular by the size, geometry and material of the dispensing opening and by a surface tension and a viscosity of the liquid. In order to overcome this flow resistance, a vibration unit is provided on at least one boundary surface of the dosing chamber and is able to cause the dosing chamber to oscillate. As a result of the oscillations, pressure waves develop in the liquid, and these pressure waves at least temporarily overcome the flow resistance of the dispensing opening. In this way, the liquid can be expelled through the dispensing opening and into an environment.